<template>
  <div class="xtx-infinite-loading" ref="target">
    <div class="loading" v-if="loading">
      <span class="img"></span>
      <span class="text">正在加载...</span>
    </div>
    <div class="none" v-if="finished">
      <span class="img"></span>
      <span class="text">{{ finishedText }}</span>
    </div>
  </div>
</template>

<script>
import { useIntersectionObserver } from '@vueuse/core'
import { onBeforeUnmount, ref } from 'vue'

export default {
  name: 'XtxList',
  props: {
    loading: {
      type: Boolean,
      default: false
    },
    finished: {
      type: Boolean,
      default: false
    },
    finishedText: {
      type: String,
      default: '亲，没有更多了'
    }
  },
  setup (props, { emit }) {
    const target = ref(null)
    //  当组件进入可视区域
  const {stop} =   useIntersectionObserver(target, ([{ isIntersecting }]) => {
      if (isIntersecting) {
        // console.log('进入可视区域')
        // 发送请求加载list数据
        if (!props.loading && !props.finished) emit('load')
      }
    }, { threshold: 0 })
    onBeforeUnmount(()=>{
      stop()
    })
    return { target }
  }
}
</script>

<style scoped lang='less'>
.xtx-infinite-loading {
  .loading {
    display: flex;
    align-items: center;
    justify-content: center;
    height: 200px;

    .img {
      width: 50px;
      height: 50px;
      background: url(~@/assets/images/load.gif) no-repeat center / contain;
    }

    .text {
      color: #999;
      font-size: 16px;
    }
  }

  .none {
    display: flex;
    align-items: center;
    justify-content: center;
    height: 200px;

    .img {
      width: 200px;
      height: 134px;
      background: url(~@/assets/images/none.png) no-repeat center / contain;
    }

    .text {
      color: #999;
      font-size: 16px;
    }
  }
}
</style>
